The invention relates to a protocol parallel processing apparatus for processing protocol in parallel at the node or terminal of the communication systems.
In the conventional telecommunication systems, each communication node or communication terminal usually processes the protocol using one CPU. If the apparatus has a plurality of CPUs such as a concentrator or a switching apparatus, the CPUs are fixedly allocated for every line or every mode of protocol such as (a) an allocation corresponding to the physical connection in which CPUs are allocated for every line or every set of the lines, or (b) an allocation corresponding to the protocol architecture in which CPUs are allocated for every layered protocol.
FIG. 9 is a block diagram of a conventional protocol processing apparatus described in the laid-open patent publication No. 61-173554, "Packet communication apparatus". In the figure, 101 is a frame processing circuit for processing the second layer of the hierarchical protocol such as the OSI protocol. 102 is a packet processing circuit for processing the third layer. 103 is a central processing portion for processing higher layers. 104 is a communication line. 105 and 106 are buses. The apparatus is allocated corresponding to the protocol construction as easily understood from the allocation of the frame processing circuit 101, the packet processing circuit 102 and the central processing portion 103.
In FIG. 9, since each of the frame processing circuit 101, the packet processing circuit 102 or the central processing portion 103 is comprised of one CPU or exclusive LSI (Large Scale Integrated circuit) and memories, the conventional protocol processing apparatus is comprised of a plurality of CPUs, each having a respective role corresponding to the protocol construction.
The protocol processing operation of the apparatus shown in FIG. 9 is explained here. In the OSI protocol representing the layered protocol, a set of information referred to as protocol data unit (PDU) is defined in each layer of the protocol and the protocol processing operation is carried out thereto. PDU is comprised of protocol control information and data. The higher layer PDU is inserted into the lower layer PDU as data. In case of PDU received from the line, the protocol is processed in turn from the lower layer to the higher layer, and in case of PDU being transmitted to the line, in turn from the higher layer to lower layer.
Accordingly, when the PDU is received through the communication line 104, the frame processing circuit 101 processes the second layer protocol at first, then processes the third layer PDU for the received PDU, and transfers the process to the central processing portion 103 if the received PDU includes a fourth layer PDU. Inversely, in case of transmitting PDU to the communication line, PDU having finished being processed in the central processing portion 103 is generated and transferred to the packet processing circuit 102. The packet processing circuit 102 generates a third layer PDU by adding third layer protocol control information to the PDU generated in the central processing portion 103 and transfers it to the frame processing circuit 101.
The frame processing circuit 101 generates a second layer PDU by adding second layer protocol control information to the PDU generated in the packet processing circuit 102 and transmits it to the communication line 104. In the conventional protocol processing apparatus, since each CPU is allocated to the respective process in the system, it is impossible to flexibly allocate other processes to the idle CPU having no job to be processed.
As described above, in the conventional protocol processing apparatus, since each processing object of the CPU is fixedly decided depending on the physical or logical construction of the communication system if the apparatus includes a plurality of CPUs in the system, the jobs of the CPUs are not necessarily effectively allocated and the performance of the CPU does not give full play.
In FIG. 9, since a plurality of CPUs have their assigned roles according to the protocol layer, if the load varies for every layer in accordance with the traffic variation or the environment of the apparatus, the CPUs can not follow the variation of the load. Accordingly all CPU can not always give full play. As a result, some resources of the apparatus will be lost without use. If loads concentrate to the specific CPU in response to the variation of the traffic, congestion occurs and the throughput of the apparatus is greatly decreased.
It is an object of the present invention to provide a parallel processing apparatus, in which the assigned roles to the plurality of CPU are not fixed to the special layers, the jobs are allocated dynamically so that the CPUs may not wait for idle processing time and the protocol processing are carried out in parallel on the plurality of the CPUs.